Conventionally, the preparation of mineral oil-derived lube base oils required drilling of crude oil which is buried underground. From a global environment point of view, to prepare mineral oil-derived lube base oils in such a manner is to add carbon buried underground to the surface circulation system of the earth. Used mineral oil-derived lube base oils may be removed by burning or discarded as liquid. During the course of burning, CO2, which would not be added otherwise, is added to the surface circulation system. When discarded as liquid, more serious problems are posed, because mineral oil-derived lube base oils possess a very low biodegradability of about 10 to about 30% (based on the CEC analysis method). The remainder (i.e. the portion not biodegraded) of the mineral oil-derived lube base oils may be absorbed to the ecosystem in the surface circulation system to cause a variety of problems. In addition, from a macroscopic point of view, the problem of serious environmental pollutants, such as S, N, heavy metals, etc. present in the crude oil drilled to produce mineral oil-derived lube base oils, being included in the surface circulation system and causing troubles can never be ignored.
In contrast, the problem of adding carbon (CO2) to the surface circulation system does not occur in the case of biomass-derived lube base oils, because biomass comes from animals or plants which are already present in the surface circulation system, which is to say that carbon already being circulated in the surface circulation system is utilized in this case. The biomass-derived lube base oils inherently have a biodegradability of at least about 70% or more and exhibit a biodegradability of nearly 100%; therefore, there is little negative impact posed on the ecosystem from burning or discharging into the nature the biomass fat-derived lube base oils which are to be discarded after use. Of course, toxic substances such as S, N, heavy metals, aromatics, etc. are not present throughout the preparation process.
Therefore, in order to overcome the above-described problems which the mineral oil-derived lube base oils have, preparation technology for a biomass-derived lube base oil has been proposed as a way to make an ecofriendly lubricating oil which has high biodegradability and is free of toxic substances (S, N, aromatics, heavy metal).